As unfortunate as that is, there's great news: you just need to keep it updated. In other words, your antivirus software only worked 100% the day you installed it. In response, antivirus software has to respond just as quickly. Those nefarious malware authors out there make new viruses every day, change how they work, and find new ways of avoiding antivirus software. © Steven Puetzer / The Image Bank / Getty Images
